Natural or man-made disasters, such as earthquakes, fires, hurricanes, and the like, can strike any place at any time. When survivors of such disasters are trapped inside collapsed buildings, burnt houses, or other hard-to-accessed places, a search-and-rescue team has very limited time to locate and save the lives of the survivors. In an earthquake rescue operation, an often-encountered rescue dilemma is whether or not to use heavy digging machinery to find the trapped survivors while not knowing where they are. Knowing the locations of the survivors allows more efficient and accurate use of the digging machinery, and therefore reduces the time to reach the survivors.
There have been a number of proposed systems for locating survivors in a disaster. For example, a “vital sign detector” was proposed to detect the heartbeat of a survivor through concrete wreckage, but its effectiveness has yet to be shown. An Enhanced 911 (E-911) system allows an emergency response team know roughly where a wireless call originates with an accuracy of a 50-meter radius or more. However, this accuracy is insufficient when it comes to determine the location of the survivors. A smartphone that subscribes to a location-based service (LBS) plan can locate itself with the global positioning system (GPS) and report its location to the service provider. The reliability of such a service in a disaster-stricken zone is unknown. There is also an emergency position-indicating radiobeacon system (EPIRS) provided mainly for cars, boat and aircraft due to the bulkiness of the system.
The advance of wireless communication have enabled widespread usage of cellular phones. Cellular phones have become one of the most pervasive devices that are carried around by people on a regular basis. However, in a disaster, cellular data and voice networks are unreliable. Cellular phones, as well as the other aforementioned systems, require an existing communication infrastructure that functions properly during a disaster. In a severe disaster, the communication infrastructure itself may be damaged.
Therefore, there is a need for a reliable and effective method, device and system for locating survivors in a disaster.